Constructors. The first uses a default sphere centered at the origin with radius 1.0; the sphere is supplied in the second. The position of the plane is specified as a fraction of the sphere radius with
the parameter
edgeTol. A tolerance value of 1.0 positions the plane down the center of the sphere. A tolerance value of 0.5 defines the longitudinal plane halfway between the center and the outside edge of the
sphere. The default value is .9, so that almost half the sphere is in front of the plane. The
orientToEye parameter determines whether the plane is perpendicular to the eye, or perpendicular to the sphere's Z axis.
Setting that parameter to TRUE (the default) specifies that the plane be perpendicular to the eye, which is most often the desired behavior.
The default view volume is undefined, and the working space
is identity.